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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

7444 results found.

  1. EP241202b: KAIT optical upper limit
  2. LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  3. EP241202b: Kinder optical counterpart candidate
  4. EP241201a: NOT optical observations
  5. EP241201a: Kinder optical counterpart candidate
  6. LIGO/Virgo/KAGRA S241102br: GRAWITA wide-field optical observations
  7. LIGO/Virgo/KAGRA S241201ac: Updated Sky localization
  8. LIGO/Virgo/KAGRA S241201ac: Identification of a GW compact binary merger candidate
  9. LIGO/Virgo/KAGRA S241130be: Updated Sky localization
  10. LIGO/Virgo/KAGRA S241130n: Updated Sky localization
  11. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  12. LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
  13. LIGO/Virgo/KAGRA S241130be: Identification of a GW compact binary merger candidate
  14. LIGO/Virgo/KAGRA S241129aa: Updated Sky localization
  15. LIGO/Virgo/KAGRA S241130n: Identification of a GW compact binary merger candidate
  16. LIGO/Virgo/KAGRA S241129aa: Identification of a GW compact binary merger candidate
  17. LIGO/Virgo S241127aj: GRANDMA/FRAM-CTA-N Observations
  18. LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
  19. EP241126a: WFST Observations
  20. GRB 241127A: Swift detection of a burst with an optical counterpart
  21. LIGO/Virgo/KAGRA S241125n: Preliminary flux estimate and spectral analysis of the Swift/BAT-GUANO candidate counterpart
  22. LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits
  23. IceCube-241127A: IceCube observation of a high-energy neutrino candidate track-like event
  24. LIGO/Virgo/KAGRA S241127aj: NED Galaxies in the Localization Volume
  25. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations
  26. LIGO/Virgo/KAGRA S241127aj: Identification of a GW compact binary merger candidate
  27. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources
  28. LIGO/Virgo/KAGRA S241126dm: Retraction of GW compact binary merger candidate
  29. LIGO/Virgo/KAGRA S241125n: DDOTI Optical Upper Limits
  30. LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
  31. LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations
  32. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on a Optical Counterpart at the BAT Position
  33. LIGO/Virgo/KAGRA S241125n: Upper limits from Fermi-GBM Observations
  34. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  35. LIGO/Virgo/KAGRA S241125n: Kinder optical upper limit in the BAT error region
  36. LIGO/Virgo/KAGRA S241125n: Updated Sky localization
  37. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  38. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  39. LIGO/Virgo/KAGRA S241109bn: Upper limits from a two-week IceCube neutrino search
  40. LIGO/Virgo/KAGRA S241125n: Updated Sky localization and Coincidence with External Event
  41. LIGO/Virgo/KAGRA S241125n: Swift/BAT-GUANO candidate counterpart
  42. LIGO/Virgo/KAGRA S241125n: Identification of a GW compact binary merger candidate
  43. LIGO/Virgo/KAGRA S241122a: Updated Sky localization and Source Classification
  44. LIGO/Virgo/KAGRA S241122a: Identification of a GW compact binary merger candidate
  45. GRB241120A: OHP/T193 optical observations
  46. GRB 241120A: Mondy and AbAO optical observations
  47. GRB 241112B: Mephisto further optical observations
  48. LIGO/Virgo/KAGRA S241116cq: Upper limits from Swift/BAT-GUANO
  49. LIGO/Virgo/KAGRA S241114y: Updated Sky localization
  50. Updates to IceCube realtime alert system for muon tracks
  51. LIGO/Virgo/KAGRA S241116cq: Updated Sky localization
  52. LIGO/Virgo/KAGRA S241116cq: Identification of a GW compact binary merger candidate
  53. GRB 241113B: Mephisto upper limits
  54. LIGO/Virgo/KAGRA S241114bi: Updated Sky localization and EM Bright Classification
  55. LIGO/Virgo/KAGRA S241113p: Updated Sky localization
  56. EP241113a: No Detection in Fermi-GBM Observations
  57. GRB 241115A: Swift detection of a burst
  58. EP 241113a: LBT possible optical counterpart
  59. GRB 241113B: KAIT Optical Afterglow Candidate
  60. LIGO/Virgo/KAGRA S241114bi: Upper limits from Fermi-GBM Observations
  61. LIGO/Virgo/KAGRA S241114bi: Coverage and upper limits from MAXI/GSC observations
  62. LIGO/Virgo/KAGRA S241114bi: Identification of a GW compact binary merger candidate
  63. LIGO/Virgo/KAGRA S241114y: Identification of a GW compact binary merger candidate
  64. Konus-Wind detection of GRB 241107A (short/hard)
  65. LIGO/Virgo/KAGRA S241113p: Identification of a GW compact binary merger candidate
  66. GRB 241113B: Swift ToO observations
  67. IceCube-241113A - IceCube observation of a high-energy neutrino candidate track-like event
  68. LIGO/Virgo/KAGRA S241111bn: Updated Sky localization
  69. GRB 241112B: LCO optical detection of the SVOM/VT candidate
  70. GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
  71. GRB 241112B: Mephisto optical upper limits
  72. GRB 241112B: Swift ToO observations
  73. LIGO/Virgo/KAGRA S241110br: NED Galaxies in the Localization Volume
  74. LIGO/Virgo/KAGRA S241109bn: ATLAS observations and discovery of the potential counterpart AT2024aawt
  75. LIGO/Virgo/KAGRA S241111bn: Identification of a GW compact binary merger candidate
  76. LIGO/Virgo/KAGRA S241110br: Updated Sky localization
  77. LIGO/Virgo/KAGRA S241110bk: 1 counterpart neutrino candidate event from an IceCube neutrino search
  78. LIGO/Virgo/KAGRA S241110br: Identification of a GW compact binary merger candidate
  79. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  80. LIGO/Virgo/KAGRA S241109bn: Updated Sky localization and EM Bright Classification
  81. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  82. LIGO/Virgo/KAGRA S241109p: Updated Sky localization and Source Classification
  83. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  84. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  85. GRB 241108A: Swift ToO observations
  86. EP241107a: Kinder optical follow-up observations
  87. EP241101a: CrAO ZTSH optical observations
  88. LIGO/Virgo/KAGRA S241106ba: 1 counterpart neutrino candidate event from an IceCube neutrino search
  89. LIGO/Virgo/KAGRA S241102o: 1 counterpart neutrino candidate event from an IceCube neutrino search
  90. GRB 241104A: The SVOM/VT candidate in GCN circular 38086 is not an astrophysical source
  91. GRB 241105A: Swift ToO observations
  92. GRB 241104A: Swift ToO observations
  93. GRB 241104A: NOT optical non-detection
  94. GRB 241105A: GOTO tentative optical counterpart candidate
  95. GRB 241104A: SVOM/VT optical candidate
  96. EP241101a: EP-FXT observations update
  97. LIGO/Virgo/KAGRA S241104a: Retraction of GW compact binary merger candidate
  98. LIGO/Virgo/KAGRA S241102cy: Updated Sky localization
  99. LIGO/Virgo/KAGRA S241102br: Updated Sky localization
  100. EP241101a: Optical upper limits with Kinder observations

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